The aims of these experiments are to deterinine high-resolution crystal structures of a variety of enzymes in a variety of ligand states. The goal of the research is to understand the mechanism of catalysis and specificity for each enzyme. In several cases the enzymes are thought to channel products/reactants to/from other enzymes, and our studies will test these hypotheses by investigation of enzymes with amino acid substitutions engineered at various sites. We have demonstrated substantial conformational changes in some enzymes during the catalytic cycle. Understanding the regulation and coordination of conformational change is also a goal of our structural studies. Monochromatic crystallography to obtain structures at the highest resolution attainable is the goal of all these studies. In general, this means using as hot a beam as possible. Data collection was done on BioCARS Station 14 ID-B.